1. Field of the Invention
The present invention relates to an illuminating plate for a car, and particularly relates to an illuminating plate such as a scuff plate or the like for indicating specific shapes with light from a light source.
The present application is based on Japanese Patent Application No. Hei. 11-351943, which is incorporated herein by reference.
2. Description of the Related Art
A scuff plate or the like designed to indicate specific shapes, specific characters, or the like, is hitherto used as an interior part of a car. For example, JP-U-6-18078 discloses a plate with an illuminator provided in a side step portion. In the plate, a light emitting portion is coated with transparent resin (light guide), and further covered with a cover in which light transmitting holes each having a desired shape are punched like windows. Thus, light from a light source is taken out through the window-like light transmitting holes provided in the cover, so that the desired shapes are indicated.
With such a configuration, the light emitting portion, the light guide plate and the cover are put on one another sequentially so that the total thickness of the plate increases. In addition, the light emitting portion is located just under the cover through the light guide plate so that a load from the plate top surface (cover surface) is applied directly to the light emitting portion. As a result, for example, if the plate is installed, like a scuff plate, in a place where the plate may be trodden by a crew who is getting on/off, a load not lower than necessary one may be given to the light emitting portion so as to damage the function of the light emitting portion.
As means for solving the foregoing problems, there is considered a method in which a light emitting portion, that is, a light source is disposed not under a light guide plate but on the side of a light guide plate so that light is introduced from a side surface of the light guide plate. In this method, for example, a reflecting layer is provided, by rough surface treatment, white print, or the like, all over the surface of the light guide plate opposite to the surface which is covered with a cover. The light introduced from the side surface of the light guide plate is reflected toward the cover by the reflecting layer provided thus, so that the light is taken out through window-like light transmitting holes of the cover. With such a configuration, however, the reflecting layer is so broad that the reflection efficiency becomes insufficient. As a result, there is a fear that unevenness appears in light emission. It is also considered that the reflecting layer is not formed all over the surface but printed like dots so as to reduce the reflection area. In this case, however, there is a fear that the light taken out through the light transmitting hole of the cover is observed to be dotted. That is not preferred in view of design.
According to a first aspect of the present invention, which has been developed in consideration of the foregoing problems, it is an object of the present invention to provide an illuminating plate of a car which can indicate a desired character, a desired figure, or the like, with a uniform light volume all over an indicating portion, and which is thin and excellent in durability. The illuminating plate has a configuration which comprises:
An illuminating plate for a car, comprising:
a light guide plate;
a light source which is located on a side end of said light guide plate;
a cover disposed on a front surface of said light guide plate and provided with at least one light transmitting window; and
at least one light reflecting layer formed on a rear surface of said light guide plate so as to cover at least a corresponding area where said light transmitting window is projected onto said rear surface, and said light reflecting layer not covering all over the rear surface of said light guide plate;
with such a configuration, the light reflecting layer is formed only in a portion corresponding to each of the light transmitting windows formed in the cover. Accordingly, the area of the light reflecting layers can be reduced, so that light from a light source can be condensed onto the whole of the light reflecting layers uniformly. It is therefor possible to make light emission with a uniform light volume all over the light reflecting layers. In addition, the light emitting portion is not provided in a position where the light emitting portion, the cover and the light guide plate are put on one another. Accordingly, the illuminating plate as a whole can be made thin. Further, the light source can be provided in any desirable position in the lateral direction of the light guide plate. Accordingly, even in the case where the illuminating plate is installed in a position where a load is given thereto, it is possible to prevent the influence of the load on the light source, so that it is possible to improve the durability.